An in-cell touch liquid crystal display device is made by incorporating touch units into the top side substrate of a liquid crystal display device, i.e., into the thin film transistor (TFT) array substrate.
The operating principle for a capacitive in-cell touch liquid crystal display device is that, because the touch capacitance of touch units is changed by touch, the touch units will convert the change of the touch capacitance to the change of voltage and transmit the change to an external signal processing unit via a reading induction line. Therefore, the external signal processing unit can detect this change of voltage and thus obtain the position of touch.
In an existing in-cell touch liquid crystal display device, the stability for signals of touch units is poor.